This feature article introduces our recent work on understanding the roles played by citrate and poly(vinyl pyrrolidone) (PVP) as capping agents in seed-mediated syntheses of Ag nanocrystals with controlled shapes. We have demonstrated that citrate and PVP selectively bind to Ag(111) and Ag(100) surfaces, respectively, and thus favor the formation of Ag nanocrystals enclosed preferentially by {111} or {100} facets. In addition, we have quantified the coverage density of PVP adsorbed on the surface of Ag nanocubes. On the basis of the mechanistic understanding, a series of Ag nanocrystals with controlled shapes and sizes have been successfully synthesized by using different combinations of seeds and capping agents: single-crystal spherical/cubic seeds with citrate for cuboctahedrons and octahedrons or with PVP for cubes and bars and plate-like seeds with citrate for enlarged thin plates or with PVP for thickened plates.
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Recent evidence suggests that grammatical aspect can bias how individuals perceive criminal intentionality during discourse comprehension. Given that criminal intentionality is a common criterion for legal definitions (e.g., first-degree murder), the present study explored whether grammatical aspect may also impact legal judgments. In a series of four experiments participants were provided with a legal definition and a description of a crime in which the grammatical aspect of provocation and murder events were manipulated. Participants were asked to make a decision (first- vs. second-degree murder) and then indicate factors that impacted their decision. Findings suggest that legal judgments can be affected by grammatical aspect but the most robust effects were limited to temporal dynamics (i.e., imperfective aspect results in more murder actions than perfective aspect), which may in turn influence other representational systems (i.e., number of murder actions positively predicts perceived intentionality). In addition, findings demonstrate that the influence of grammatical aspect on situation model construction and evaluation is dependent upon the larger linguistic and semantic context. Together, the results suggest grammatical aspect has indirect influences on legal judgments to the extent that variability in aspect changes the features of the situation model that align with criteria for making legal judgments.
We report a one-step method for facile and sustainable synthesis of magnetic iron oxide nanorods (or IONRs) with mean lengths ranging from 25 to 50 nm and mean diameters ranging from 5 to 8 nm. The prepared IONRs are highly stable in aqueous media and can be surface functionalized for biomarker-targeted applications. This synthetic strategy involves the reaction of iron(III) acetylacetonate with polyethyleneimine in the presence of oleylamine and phenyl ether, followed by thermal decomposition. Importantly, the length and diameter as well as the aspect ratio of the prepared IONRs can be controlled by modulating the reaction parameters. We show that the resultant IONRs exhibit stronger magnetic properties compared to those of the widely used spherical iron oxide nanoparticles (IONPs) at the same iron content. The increased magnetic properties are dependent on the aspect ratio, with the magnetic saturation gradually increasing from 10 to 75 emu g-1 when increasing length of the IONRs, 5 nm in diameter, from 25 to 50 nm. The magnetic resonance imaging (MRI) contrast-enhancing effect, as measured in terms of the transverse relaxivity, r2, increased from 670.6 to 905.5 mM-1 s-1, when increasing the length from 25 to 50 nm. When applied to the immunomagnetic cell separation of the transferrin receptor (TfR)-overexpressed medulloblastoma cells using transferrin (Tf) as the targeting ligand, Tf-conjugated IONRs can capture 92 ± 3% of the targeted cells under a given condition (2.0 × 104 cells/mL, 0.2 mg Fe/mL concentration of magnetic materials, and 2.5 min of incubation time) compared to only 37 ± 2% when using the spherical IONPs, and 14 ± 2% when using commercially available magnetic beads, significantly improving the efficiency of separating the targeted cells.